Manufacture of car-axles.



A. C. CUNNINGHAM. MANUFACTURE OF CAB AXLES. APPLICATION FILED D20. 21. 1900.

1,068,630. Patented July 29, 1913.

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A. C. CUNNINGHAM.

MANUFACTU E OF GAR AXLES.

APPLICATION FILED D110, 21I I909.

Patented July 29, 1913.

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UNITED STATES PATENT oration ANDREW C. CUNNINGHAM, 0F NORFOLK, VIRGINIA.

"MANUFACTURE OF CAR-AXLES.

Application filed December 21, 1909.

To all whomit may con (367")1 Be it knop'n that I. ANDREW C. CUNNING- iuiu. a citizen of the United States, and

resident of Norfolk, count; of Norfolk, and

State of irg'inia. have invented certain new and useful Improvements in the Manufac ture of Car-Axles: and I do hereby declare the following to he a full. clear. and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the n'ianut'acture of car axles of the standard type and in particular to inethmls ot'rolling such axles ac-- cording to which a ftlttlltl or billet is passed longitudinally through several tains of rolls, or through several separate passes of the same rolls, the rolls taking the form of dies that impress, into the round the desired pattern. The dies effect a lengthening and reduction of the round at the same time that the desired shape is heing'graduallv protl-i'ced by the successively acting passes. 1n niethtuls of this clniracier. which embody no rolling other than a longitudinal one, considerable difiicultv arises in giving to the axle its proper final shape. and the requisite straightening out and hardening of the formed axle is usually effected by means of a complicated and iuisrtistactory process that is entirely iinlependent of the rolling operation and forms an entirely separate step. necessitating various inanipulatit'ins of the partially formed axle andseveral heatings of the latter. Again, axles manufactured in this .way do not have the requisite hardness at the exterior surfaces, and the structure of the steel through the axleas a whole is not uniform. which is often due to the fact that the article is forged after rolling, and that it is well nigh impossible to obtain a uniform hardness-throughout the leng'th of the axle.

The object of the present invention is to obviate these defects in the present unsatisfac ory methods of producing rolled axles, and to furnish a method which provides in a simple and effective Way for the straightening, hardening and finishing of the axles after they have been rolled longitudinally and while they retain the original heat, so that the entire process of'longi'tudinally rolL ing the axles to produce a elose'approximation of the final shape, and also ofstraighten-irg hardening and finishing suchiaxles takes place Without using any heat other Specification of Letters Patent.

Patented July 29, 1913.

Serial 1%. 534,524.

than that which given by the furnaees out of which the original ingots are taken prior to the division of each ingot into the billets or rounds, from which the axles are lash ioned.

According to this invention the straight ening, hardening and finishing; of the par tially formed axles eti'ected by cross roll; of appropriate form through which they are passed when they come out of the last longitudinal train, and this operation takes place at a time when the axles have just the proper heat for the hardening process. It also proposed to temper the axles during the erossrollin r so that great hardness and toughness will be obtained by the simultaneous condensing act-ionof the cross rolls and the hardening that is derived from the blast of air water or other fluid that is (lit-- rec-ted against. the axle at this stage of the proceeding. and itwill be manifest that in llll way a considerable simplification of process as a whole is obtained, the axle'ht ing then read for turning down in a lathe though it has been Found that in this latter operation it is only necessary to remove an extremely small amount of the surface metal It is also apparent: that this not onl brings about great economy in the use of the steel but prevents the removal of the greater part of the hardest metal, viz. the metal at the surface of the axle. In carrying out. the process it is preferable to produce a number of axles from the same round or billet which axles are connected during the longitudinal rolling. but cut apart for the cross rolling and finishing, and this simultaneous fora inn of a number of axles can also be carried out at a single heat, as above indica ed.

In the accompanying drawing: Figure 1. is a diagrammatic plan view of a rolling mill plant such as is used iincarry-ing out the improved method; Fig. is a transverse sec-- tion through a train of rolls for longitudinal rolling; Figs. 3, 4 and 5 illustrate the round as it appears at different st ages of the longitudinal rolling; Fig. G shows the mrtially formed axle as it ai'ni ars after passing through the straightening and harden; cross rolls; and Fig. 7 shows the it axle, it appears after iinal Ina Referring particularly Fig i to carry on the manufacture t in a plant comprising furnac An :1 ing mill B. to form the hot ii 1 lets or rounds of the requi ite 325 an;

' two or more,

shape; a hot sawfQto cut off the crop end of the round mills D, D and Date effect the longitudinal rolling of the round; hot;

saws E, by which the partially-formed axles in the round are cut. away from each other; and cross rolls F, F, wh ch-effect the hardening and finishing of the separate axles. It to be understood, howei er, that 1 do not limit myself to the use of any special apparatus and that the general an rai'igrment of the plant is capable of wide modification. The form "of the furnaces, blooming mill, and hot saws is entirely immaterial to the invention, and the mills- D, I), D'-, which may be variedin number and arrangement, only need to have the general characteristics shown in Fig. 2, that is to say, the upper and lower roll's 10, 1 1, thrmighwhich the round is passed axially,

'- need only be provided with such projections associated -therewith, is illustrated in my Patent No. 938,827, dated Nov. 2, 1909.

in carrying out the improved method, the ingots are'transferred from the furnaces A to the blooming mill B, by means of which they are formed ina well known way into suitable'rounds of the requisite length and diameter, such rounds being turned out: of

he blooming mill while -still at' a comparatively nigh heat. As each round. is taken outof this mill, it is passed to the hot saw C,'which cuts oil the crop end. The

round then starts through theseries of'rolls' D, D, D, which-are preferably in alinement,,

5 shown. Assuming for purposes of description that a car axle of-simpleform is to be made, although an axle with as many shoulders and diameters as desired would be made in the same way, the passage of the round throngh'the first mill D only gives it a rotigh approximation of the final finished axle. This makes an'easy draft on the hot metal and prevents cracks and fracture. It is not necessary to limit the original round to a length that will produce oneaxle, but it is preferable to have it long enough to produce as above indicated, and in this case the rolls are of such sizeand shape to impress in the round a numberof continuous patterns, so that after-passing through the first mill, for instance, the round takes the form shown in Fig. 3. It will be noted that the roughly, formed axles shown in this figure are connected by a, portion 12,.and that at the extreme end of the round there is a smooth portion 13. The partly shaped r und then passes onto the next mill D- and is further lengthened and reduced and brought toward the final shape; in this sec- 0nd mill the junctions between the ditl'erent diameters may be made oneasy curves or.

as many mills of this kind may be used as desired inorder to make the draft or disj tortion-on the hot metal sufliciently easy and to perfect the junctions between the difi ere/ut diameters. After the round has had t me or .more axle shapes rolled into it by the s eral longitudinal mills it is passed to he grouper hot saws E where it is sawed into its individual axles. The end (13) of the first or leading axle, the junctions (12 between the axles, and the end of the last axle (notshown), are purposely made of extra length as, compared with the finished machined axle, as this saves fine adjustment in placing the round in. position 'for hot sawing and gii'essurplus length for finishing the axle to length in a lathe. -The various cylinders or shaped portions are also made of lengths which permit the desired machining to' produce afinished axle of vthe required dimen sionsl The 'surplusat the ends-also allows for variation in shrinkage due/to th'e variation in temperature, asdoes also the mak- "ng of the various cylinders and shaped, ortions somewhat larger than the machine dimen'sions. last mill D and from the hot saw's'E, need not be perfectly straight or truly round; for a tempered axle it is preferable-that they should be of an'elliptical or flattened section, in which case the passes of the longitudinal rolls are made of appropriate profile. When the round reaches the hot saws E it'will retain suflicient heat to permit the proper operation-of the latter and after the udividual axles have been severed from each other (Fig. 6,) they pass in the finishing and tempering cross rolls F, F by which they are straight ed and the various cross sections made ii' uly round; at the same time, the axle can be tempered if desired, by directing against it, while it is being straightened and condensed by the cross rolls,a blast of air, water, oil or other fluid, aswill'be well understood in the art, the axle retaining suflicient'heat to undergo properly. 'l'n this way the shaping, finishing and tempering of a number of axles rolled longitudinally while connected together in a single round, may be effected at a single heat, and there is therefore not only a great simplification of the operation as a whole but also great uniformity and den- -sity in the finished axle, which will be found he axles, as. they come from the this operation to be perfectly straight and of great hardmedium. The hardestv tempers are produced ness, ductility and strength. The surplus from the highest initial heats, and mercury whichis left on'the end of the axles when will produce a much harder temper than the latter are severed from each other and l oil. Cold water will also produce a much 5 cut. along the lines a, (1 and I), 1) indicated on 1 harder temper than boiling water.

Fig. is of advantage in the finishing rolls 1 According to this process the temper of for preserving the final collar, that is subthe different parts of the axle can be varied sequently machined, from being fractured, i if desired. The journal can be made hard. and in keeping the end perfectly straight l the wheel seat more moderate, and the cen- 10 and protecting it during tempering. ,After i tral portion of the axle, which is subject to l l l the axle has been straightened, rounded and i the greatest bending strains, still softer.

tempered, if desired, and has taken the form This is done by varying the time of applishown in Fig. 6, it, is-ready for its final cation of the ditferent parts of the l)last,and machining, which will give it the shape also by the duration of the time of applica- 15 illustrated in Fig. 7. By carrying out the 1 tion of the different parts: also, I can go process in the manner described the ma- 5 still farther, and vary the temperature of hitting is reduced to a minimum. and the l the different parts of the blast. All this, waste or scrap is made almost negligible; l it is apparent, is very simple in applicano this also has the result that a maximum tion. As a result the axle may be of uniamount of the most highly refined metal. to form or varying temper, as desired. on ion \vit, thatv at the surface of the axle, is re-' gitudinal elements. and of uniformly varytained. ing temper on radial elements. 50

The longitudinal rolls l), 1). l) may have i 'hatv I claim is 2-- a. single groove 'or' pass, in which case they A method of rolling car axles which X :n-

priscs passing a suitable round or bilt i 10]]- i will he changed for each different pattern that of axle, or they may have several grooves gitudinally through a series of r or passes, each for a different pattern of impress into it a pattern approximat ,ehat axle, which will permit different patterns of the finished axle, and then strai; dening to be made without changing the rolls, or and finishing the axle by passing iiin a I 30 different patterns may be made successively transverse direction through suitable cross at the same rolling: In the latter case the 1 rolls: substantially as described. finishing and tempering passes will have In testimony whereof I afiix niy sigaature, rolls corresponding to the patterns of the t in presence of two witnesses.

, axles that are bcin rolled. i Y a 7 t y 0 The degree of tefiiper depends on the dif- CUNNINGHAM fcrcnce of initial and final heat, and also on the rate of cooling, the latter being intlucnced by the temperature of the cooling \V itnesses (1. D. Tnmmna, Ennis B. NoYiw 

